The present invention relates to metal-working machines and more specifically it relates to the profile-grinding machines used for machining convex-shaped articles.
The machine realized in accordance with the present invention will be used most successfully for grinding the backs of curved turbine blades.
Widely known in the art are profile-grinding machines for machining convex-shaped articles, mainly turbine blades, which comprise a bed mounting a grinding stock carrying the grindstone, and a mechanism for dressing said grindstone. The same bed mounts a movably installed bed plate which carries freemoving headstock and tailstock of the work.
The axle located between the headstock and tailstock carries an arbor for the work, and a master form. The master form interacts with a contact member in the form of a follow-up roller whose shape and dimensions correspond to those of the grindstone. As the master form starts rotating, the follow-up roller profiles the work via a mechanical (hydraulic or electrical, etc.) profiling system which actuates the grinding stock with the grindstone, or the bed plate with the work stocks.
The working surface of the grindstone follows a radius or a complex curve, the curvature in the longitudinal and transverse sections of the grindstone being different.
As the grindstone becomes gradually worn in operation and its cutting properties, shape and dimensions are restored by the dressing mechanism this leads to mismatching of the dimensions of the grindstone and follow-up roller which necessitates frequent replacement of the latter. Frequent changes of the follow-up rollers involving highly accurate installation and adjustments cut down the efficiency of the machines and hinder the rational utilization of the abrasive tools. In addition, the use of the follow-up roller in the capacity of the contact member limits the maximum possible diameter of the grindstone since the follow-up roller should have the same dimensions as the grindstone; this, in turn, makes the machine more bulky and complicates the replacement of the follow-up rollers which is called for by the wear of the grindstone.
Another disadvantage of the known machines lies in the difficulty with which the master form and arbor are reset relative to each other and to the follow-up roller and grindstone when the machine has to be switched over to grinding the articles of different dimensions.